Interpretive Summary: To secure US genetic diversity it is beneficial to compare US and non-US breeds. Such information may also be used to identify areas of sampling for diverse genetic resources. Kazakhstan (KZ) provides an interesting comparison due to its history of sheep production and proximity to the Silk Route, which likely facilitated genetic migration from the Fertile Crescent to China. With microsatellite markers it is possible to quantify genetic differences between US and KZ sheep breeds. Five KZ breeds were sampled: Arkharo-Merino (AM), Chyisskaya (CHY), Degresskaya (DEG), Edil’baevskaya (EDI), and Sary-arkinsskaya (SA). The AM is a hybrid between wild Arkhar rams (Ovis ammon) and Merino, Precoce and Rambouillet ewes (Ovis aries), the other four breeds are coarse wooled and fat rumped. The 13 US breeds included: fine wool, meat types, long wool, hair, prolific, and fat rumped. The KZ breeds tended to have greater genetic diversity. However, the US Rambouillet and Dorper were similar to KZ breeds. The KZ breeds had higher levels of heterozygosity when compared to US breeds. Among the four fat-rumped KZ breeds the genetic distances were relatively small, despite large geographic differences in sample derivation. The genetic distance between AM and Rambouillet (0.13) was unexpected given the Ovis ammon component of the AM, and suggests that during the formation of the AM that many of the genes associated with the Arkhar were selected against resulting in a population that is primary comprised of Merino/Rambouillet. Concluding, these results indicate substantial genetic distance and variability between the US and KZ breeds evaluated, except for the AM and Rambouillet. The results also illustrate that genetic diversity is greater near the center of domestication.

Technical Abstract:
To secure US genetic diversity it is beneficial to compare US and non-US breeds. Such information may also be used to identify areas of sampling for diverse genetic resources. Kazakhstan (KZ) provides an interesting comparison due to its history of sheep production and proximity to the Silk Route, which likely facilitated genetic migration from the Fertile Crescent to China. With microsatellite markers it is possible to quantify genetic differences between US and KZ sheep breeds. Five KZ breeds were sampled: Arkharo-Merino (AM), Chyisskaya (CHY), Degresskaya (DEG), Edil’baevskaya (EDI), and Sary-arkinsskaya (SA). The AM is a hybrid between wild Arkhar rams (Ovis ammon) and Merino, Precoce and Rambouillet ewes (Ovis aries), the other four breeds are coarse wooled and fat rumped. The 13 US breeds included: fine wool, meat types, long wool, hair, prolific, and fat rumped. Blood and semen samples were collected from both countries (n = 24.5/breed). DNA was extracted and genotyped using 29 FAO/ISAG panel microsatellites. Genotype data were analyzed using GENALEX and PHYLIP. The KZ breeds had greater allelic richness when compared to US breeds (7.8 vs 4.8, respectively). However, Rambouillet and Dorper were similar to KZ breeds with average allele numbers of 8.2 and 7.5, respectively. The KZ breeds had higher levels of heterozygosity when compared to US breeds. Among the four fat-rumped KZ breeds the genetic distances were relatively small (< 0.14), despite large geographic differences in sample derivation. Dorper and Karakul were the US breeds most closely associated with the CHY, DEG, EDI, and SA with genetic distances ranging from 0.22 to 0.35. The genetic distance between AM and Rambouillet (0.13) was unexpected given the Ovis ammon component of the AM, and suggests that during the formation of the AM that many of the genes associated with the Arkhar were selected against resulting in a population that is primary comprised of Merino/Rambouillet. Concluding, these results indicate substantial genetic distance and variability between the US and KZ breeds evaluated, except for the AM and Rambouillet. The results also illustrate that genetic diversity is greater near the center of domestication.